Due to hefty 3G roaming rates, Apple’s Maps app just won’t cut it when you’re out of the country. The oMap app lets you download maps for offline viewing — dodging a shocking bill post-vacation.

The iPhone is an almost perfect companion for travels to distant lands. With a bit of foresight and time set aside for planning, it’s possible to mix and match the perfect blend of vacation apps, ensuring you make the most of your journey.

My own package of essential travel tools includes Evernote, QuadCamera, Gengo Flashcards and HearPlanet. Without a 3G connection overseas, though, Apple’s Maps app proves utterly redundant — if I can’t connect, I can’t use it.

oMaps brings offline mapping to the iPhone. The app includes GPS, multiple zoom levels, map bookmarking and search functionality.

Don’t Google It

Notably, oMaps doesn’t make use of Google Maps. The developer, Thomas Bonnin, cites licensing restrictions from Google as the reason. Instead, the app utilizes OpenStreetMap, a service referred to by Bonnin as “the Wikipedia of maps.”

Despite being a community-maintained mapping service — meaning that there may be lower detail in some areas — in practice, the maps seem to be accurate, detailed and certainly useful for tourists. Even better, OpenStreetMap includes restaurants, ATMs, bus stations and other notable landmarks — a boon for lone travelers.

Best of all, because oMaps makes use of an open-source solution, after purchasing the app, individual maps are free to download. Admittedly, in-app purchasing of new maps would have been a neat iPhone OS 3.0 feature, although for me to grumble about that is akin to performing extended dental work on a gift horse.

Making Your Map

To create a new offline map, you simply open the app, browse to the location you’d like to view later and click save. Maps can only be downloaded via Wi-Fi, due to potentially large download sizes (the app saves the current zoom level and each increasing level of detail beyond that).

Although the developer states that you can save unlimited maps, there is one major constraint. The app will only start saving a map from a certain level of detail. If you zoom too far out — in my case when trying to download all of Helsinki — oMaps will refuse to save.

Essentially, the app draws a line as to how much you’re able to download in one go. It certainly doesn’t ruin the app or its functionality, but it’s a seemingly arbitrary obstacle, surpassed simply by downloading a given area in several separate chunks.

On Your Travels

Downloading a useful portion of a given city takes time and requires a stable connection. To make the best use of oMaps, you’ll need to plan ahead and prepare at least a day or so before traveling.

Once you’re offline and on the move, the app comes into its own. For me, flipping the iPhone to Airplane Mode and opening oMaps felt like cartographical witchcraft — the app located me immediately and I could zoom in and out, viewing my surrounding area in various levels of detail.

It’s worth clarifying for less tech-savvy users how this works. Your data connection — 3G, Edge, GPRS — may cost money to use overseas, usually at an inflated rate. The GPS in your iPhone — used for locating you — is free. oMaps uses the GPS to locate you and requires no data connection because the data itself, the map, has already been downloaded and saved to your iPhone.

Just like Apple’s Maps app, oMaps includes a GPS button. Pressing the button will locate you, assuming you’ve downloaded the corresponding map for the area you’re occupying. There are a few differences and drawbacks, though.

Unlike Maps, once you’re on the move, there are no directions or search functionality. Directions may be an arguably complex function, however Search does seem like something that could have been achieved — even if it means downloading a little more data when initially saving the map.

Summing Up

The app has a few issues that, while irritating, don’t ruin the overall functionality. Saving multiple maps for one city can be a drag, but then it’s all free and can be used offline, even with GPS. Plus, the lack of search functionality means that you may have to do a little extra pre-planning before setting off.

Rather than comparing oMaps to Apple’s Google-powered Maps, it’s perhaps best to see the app as a replacement to a traditional map. It saves purchasing horrid foldout maps and, as such, is more discreet and agreeable for meandering tourists.

Most importantly though, oMaps is a time and money saver. Although it won’t prove useful at home, when you’re in foreign lands this really will be an essential app.